Carbon nanotubes have been manufactured on substrates in a variety of different ways. Many methods of manufacturing carbon nanotubes involves the use of significant amounts of heat. This heat adversely affects semiconductor circuitry already formed on the substrate. Such circuitry exhibits further doping migration and other changes when its thermal budget is exhausted.
As the methods of manufacturing carbon nanotubes improves, more uses for them are being discovered. A further problem is obtaining selective growth patterns for the nanotubes to accomplish desired functions.